UV-Blocking Layer for Silver Nanostructure Optical Stack Stability

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Solution Overview

Problem

Silver nanostructure-based transparent conductive films are prone to corrosion due to light exposure, leading to unstable sheet resistance and unreliable performance in optical stacks, 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 block or attenuate UV light, which is placed between the light source and the silver nanostructures, thereby preventing photodegradation and maintaining stability of the transparent conductive films.

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 component between the light source and the silver nanostructure-based transparent conductive film. This intermediate layer selectively absorbs or blocks UV radiation while allowing visible light to pass through, thereby preventing the harmful UV light from reaching and corroding the silver nanostructures. The UV-blocking layer acts as a protective mediator that filters out the specific wavelength range responsible for photodegradation without interfering with the optical and electrical functionality of the underlying conductive film.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The UV-blocking layer is applied in advance to the substrate before or during the formation of the silver nanostructure-based transparent conductive film. By establishing this protective barrier beforehand, the system preemptively prevents UV light from causing corrosion to the silver nanostructures. This preliminary protective action ensures that the conductive film maintains its stability and reliability from the outset, avoiding the need for subsequent repairs or replacements due to light-induced degradation.

Inventive Principle:

Principle #10Preliminary action

2Reliability

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

Engineering Contradiction:

Improvestability under light exposureVSAvoidnumber of layers in optical stack

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The UV-blocking layer is designed to serve multiple functions simultaneously: it blocks UV radiation to prevent corrosion, maintains optical transparency for visible light transmission, and can be integrated with existing optical stack layers. By making the UV-blocking layer multi-functional, the patent avoids the need for separate protective layers and maintains compatibility with the overall device architecture, thereby minimizing the increase in device complexity while achieving improved reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent optimizes the optical parameters of the UV-blocking layer, specifically its transmission characteristics. The layer is engineered to have high transparency in the visible spectrum (400-700 nm) while providing effective UV blocking (below 400 nm). By carefully controlling the transmission parameters and selecting appropriate materials with suitable optical properties, the UV-blocking layer can be integrated into the optical stack without significantly impacting the overall optical performance or adding excessive complexity to the device structure.

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 stability of the optical stacks under prolonged light exposure, with sheet resistance remaining stable for extended periods without significant increases in resistance values.

Implementation Method 1

Incorporating a UV-blocking layer in the optical stack to block or attenuate UV light

Methodology Applied

Scientific EffectUV-blocking: Absorption (EM radiation)

Implementation Method 2

UV light and oxygen promote oxidation reactions

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS11137863B2Silver nanostructure-based optical stacks and touch sensors with UV protection

Publication Date: 2021.10.05 PINE CASTLE INVESTMENTS LTD

AI summary

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