Laminated Touch Panel Wiring for Low Reflection and Resistance
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Solution Overview
Problem
Existing touch panel structures for outdoor use face challenges in achieving low reflection and high transmittance while maintaining low electrical resistance, leading to performance degradation and design limitations, particularly with the use of transparent conductive films and metal wiring, which complicates manufacturing and affects the aperture ratio and connectivity.
Innovation Solution
A touch panel structure with laminated wiring comprising a low-reflection film, a conductive film, and a transparent film, where the low-reflection film is on top, and an insulating film covers the wiring, with selective openings in the lead-out region to protect the conductive film from alkaline developing solutions, allowing for the use of low-resistance materials like aluminum without performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If transparent conductive film is used for touch sensor wiring, then light transmittance is improved, but electrical resistance increases
Solution Approach 1:
The patent uses a composite wiring structure combining transparent conductive film (ITO) with metal film (aluminum) in sequence. The ITO layer provides transparency and light transmittance, while the aluminum layer provides low electrical resistance. This composite structure resolves the contradiction by integrating materials with complementary properties to achieve both optical and electrical performance requirements simultaneously.
2Reliability
If metal material is used for connection terminal portion, then electrical resistance is improved, but reflection to incident light increases
Solution Approach 1:
The patent applies a low-reflection film (nitride film) over the metal aluminum layer in the connection terminal portion. This creates a composite structure where the aluminum provides low electrical resistance while the nitride film suppresses light reflection. The combination resolves the contradiction between electrical conductivity and optical reflection properties.
Solution Approach 2:
The patent changes the surface properties of the metal layer by depositing a nitride film with specific optical characteristics. This parameter change modifies the reflection properties of the metal surface while preserving its electrical conductivity, thereby resolving the contradiction between low resistance and low reflection.
3Ease of manufacture
If color filter is formed after touch sensor wiring, then manufacturing process is simplified, but conductive film is damaged by alkaline developing solution
Solution Approach 1:
The patent introduces a low-reflection film (nitride film) as an intermediary protective layer between the conductive film and the alkaline developing solution. This intermediary layer protects the conductive film from chemical damage during color filter formation while allowing the manufacturing process to proceed in a simplified sequence. The nitride film acts as a barrier that prevents alkaline solution from damaging the underlying aluminum conductive layer.
Solution Approach 2:
The patent applies the low-reflection film to the conductive film before forming the color filter. This preliminary protective action prevents damage to the conductive film during subsequent alkaline developing processes. By preparing the conductive film structure in advance with protective coating, the patent enables simplified manufacturing sequencing without compromising conductive film integrity.
4Area of stationary object
If wiring width is reduced, then aperture ratio is improved, but electrical resistance increases
Solution Approach 1:
The patent uses a composite structure of transparent conductive film and metal film to maintain low electrical resistance even with reduced wiring width. The metal aluminum layer provides high conductivity that compensates for the reduced cross-sectional area, allowing thin wiring (50-100nm ITO + appropriate aluminum thickness) to achieve both high aperture ratio and low resistance.
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 enables the production of touch panels with low resistance and low reflectance characteristics, improving outdoor visibility and reducing manufacturing costs by simplifying the structure and preventing damage to the conductive films during the color filter formation process.
Implementation Method 1
a low-reflection film, a conductive film, and a transparent film laminated in this order
Implementation Method 2
A transparent conductive film that has a relatively high resistance compared with metal in a display portion, has a low reflection to incident light from the outside of a display apparatus, and has high transmittance of light from a light source for display is used for wiring of the touch sensor
Implementation Method 3
has high transmittance of light from a light source for display
Data Source
AI summary
A contact hole that penetrates a protective insulating film, an interlayer insulating film, and a transparent cap film and has a surface of a low-reflection film uncovered as a bottom surface is formed in a lead-out wiring region. A lower-layer terminal portion is formed by the low-reflection film and a low-resistance conductive film below the bottom surface of the contact hole. A contact hole that penetrates the protective insulating film and a transparent cap film and has a surface of a low-reflection film uncovered as a bottom surface is formed in the lead-out wiring region. An upper-layer terminal portion is formed by the low-reflection film and a low-resistance conductive film below the bottom surface of the contact hole.