UV-Blocking Optical Stacks for Stable Silver Nanostructure Sensors

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Solution Overview

Problem

Silver nanostructure-based transparent conductive films in optical stacks are prone to corrosion due to light exposure, leading to unstable sheet resistance and unreliable performance, particularly at the interface of light and dark regions, where UV light and oxygen promote oxidation reactions.

Innovation Solution

Incorporating a UV-blocking layer in the optical stack to absorb or attenuate UV light, thereby preventing degradation of silver nanostructures and maintaining stable sheet resistance over extended periods of light exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If silver nanostructure-based transparent conductive films are used, then electrical conductivity and optical transparency are improved, but stability and reliability deteriorate due to light-induced corrosion

Engineering Contradiction:
Improvestability of sheet resistanceVSAvoidlight-induced corrosion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

An UV-blocking layer is introduced as an intermediary between the silver nanostructure-based transparent conductive film and the incident light. This layer selectively absorbs or reflects UV wavelengths while transmitting visible light, thereby protecting the silver nanostructures from UV-induced corrosion without compromising optical transparency or electrical conductivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The UV-blocking layer converts potentially harmful UV radiation into a beneficial protective function. By absorbing UV energy, the layer prevents it from reaching and corroding the silver nanostructures, effectively using the UV energy to protect rather than damage the underlying functional layers.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If UV-blocking layer is added to optical stack, then stability and reliability are improved by preventing corrosion, but device complexity increases

Engineering Contradiction:
Improvestability of sheet resistanceVSAvoidnumber of layers in optical stack
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The UV-blocking layer is designed to perform multiple functions simultaneously: it blocks UV radiation, maintains optical transparency in the visible range, and provides a stable interface with adjacent layers. This multi-functionality reduces the need for additional separate protective layers, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The UV-blocking layer's optical properties are optimized by adjusting its thickness and material composition. By carefully controlling these parameters, the layer achieves effective UV blocking while maintaining high visible light transmission, thus protecting the silver nanostructures without significantly impacting the overall optical performance or adding excessive complexity.

Inventive Principle:
Principle #35Parameter changes

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 UV-blocking layer effectively prevents localized photodegradation, ensuring the optical stack's stability and reliability by blocking UV light from interacting with silver nanostructures, thus extending the duration before significant sheet resistance increase occurs.

Implementation Method 1

Incorporating a UV-blocking layer in the optical stack to absorb or attenuate UV light, thereby preventing degradation of silver nanostructures

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

where UV light and oxygen promote oxidation reactions

Methodology Applied
Scientific EffectPhoto-oxidation: Photo-oxidation

Data Source

PatentEP3049905B1Silver nanostructure-based optical stacks and touch sensors with UV protection
Publication Date: 2020.03.04 CAMBRIOS FILM SOLUTIONS CORP
  • EP3049905B1 patent drawingFigure 1~2B
  • EP3049905B1 patent drawingFigure 3~5
  • EP3049905B1 patent drawingFigure 6(a)~6(b)

AI summary

Disclosed herein are optical stacks that are stable to light exposure by incorporating one or more UV-blocking layers.