Aligned Silver Nanowire Film for Touch Position and Force Sensing
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Solution Overview
Problem
Existing touch screen panels struggle to simultaneously recognize touch position and strength due to limitations in durability and random arrangement of transparent conductive films, leading to high contact resistance and surface roughness, which hinders flexible touch screen panel manufacturing.
Innovation Solution
A silver nanowire film with unidirectionally aligned nanowires and a mechanochromic complex polymer is used, where the alignment degree of silver nanowires is controlled to form a high-conductivity, transparent electrode, and a touch screen panel is designed with a location recognition layer and a strength recognition layer to visualize contact strength through color change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If generally known solution process is used for silver nanowire coating, then coating process is simple and easily applied, but silver nanowires are randomly arranged and entangled causing high contact resistance and high surface roughness
Solution Approach 1:
The patent divides the nanowire arrangement into two distinct types: unidirectionally aligned nanowires and randomly arranged nanowires. This segmentation allows the conductive network to benefit from both ordered pathways (low resistance) and random distribution (good coverage), resolving the contradiction between manufacturing simplicity and arrangement precision.
Solution Approach 2:
The patent applies different arrangement qualities to different regions of the conductive film. By creating zones with unidirectional alignment alongside randomly arranged areas, the film achieves locally optimized properties that collectively solve the overall contradiction between easy manufacturing and precise arrangement.
2Ease of operation
If transparent conductive film is used in resistive touch panel, then touch position can be recognized, but durability deteriorates due to repeated and continuous pressure
Solution Approach 1:
The patent uses composite materials combining silver nanowires with polymer matrices. This composite structure provides both the electrical conductivity needed for touch position recognition and the mechanical flexibility required for durable flexible touch screens, resolving the contradiction between operational functionality and reliability under repeated pressure.
3Measurement precision
If resistive touch panel structure is used with upper and lower transparent conductive films, then touch position can be recognized through contact, but touch strength cannot be recognized and only simple positional information is displayed
Solution Approach 1:
The patent makes the transparent conductive film multi-functional by enabling it to perform both touch position recognition (through its conductive properties) and touch strength recognition (through mechanochromic color changes). This universal application resolves the contradiction by allowing a single component to provide both positional and force information without requiring separate systems.
4Reliability
If silver nanowires are aligned unidirectionally to improve conductivity, then electrical properties improve, but manufacturing complexity increases
Solution Approach 1:
The patent employs self-aligning mechanisms where the nanowires automatically orient themselves during the coating process through their aspect ratio and interaction with the coating flow. This self-service approach achieves unidirectional alignment and improved conductivity without requiring complex external alignment equipment or multi-step manufacturing processes.
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 efficient recognition of both touch position and strength with improved durability and uniform electrical conductivity across large areas, enhancing the performance of flexible touch screen panels.
Implementation Method 1
silver nanowires A unidirectionally aligned in a longitudinal direction
Implementation Method 2
a mechanochromic complex polymer of which a color is changed according to the touch strength
Implementation Method 3
excellent conductivity, transparency, and flexibility
Data Source
AI summary
Disclosed is a silver nanowire film including: silver nanowires A unidirectionally aligned in a longitudinal direction; and silver nanowires B randomly aligned in the longitudinal direction, in which the silver nanowires A and the silver nanowires B each are plural and satisfy Equation 1 below.[A]/([A]+[B])>⅔ [Equation 1](In Equation 1 above, [A] represents the number of silver nanowires A having an alignment degree of less than ±15° from the alignment direction, and [B] represents the number of silver nanowires B having an alignment degree of ±15° or more from the alignment direction.)