Moth-Eye Optical Element for Surgical Face Shield

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Solution Overview

Problem

Conventional face shields used in surgical operations suffer from significant light reflection and fogging issues due to high-intensity surgical lighting, leading to glare and reduced visibility.

Innovation Solution

A face protective optical element with fine and dense irregular structures, known as 'moth-eye' structures, are formed on both surfaces of a flexible transparent substrate, reducing light reflection and ensuring hydrophilicity to prevent fogging, thereby enhancing visibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a flexible transparent plastic film is used for face protection, then the face can be protected from flying objects, but light reflection occurs at the air interface reducing visibility

Engineering Contradiction:
Improvelight reflectionVSAvoidvisibility
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent divides the surface of the transparent film into multiple micro-scale protruding structures (moth-eye structures) with a pitch of 0.1-10 μm. This segmentation creates gradual refractive index transitions between air and the film material, reducing light reflection from 10.1% to below 1%, thereby improving visibility while maintaining protective function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs curved or conical protruding structures on the film surface rather than flat surfaces. These curved geometries create gradual optical transitions that reduce refraction and reflection at the air-film interface, directly addressing the visibility problem caused by light reflection while preserving the film's protective capability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Object-affected harmful factors

If a transparent plastic film with refractive index 1.3 or more is used, then protection is provided, but reflection on front and rear sides generates up to 10.1% reflected light

Engineering Contradiction:
Improvereflected light ratioVSAvoidfield of view clarity
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The surface is segmented into numerous micro-protrusions with controlled pitch and dimensions. This segmentation transforms the single large air-film interface into multiple small interfaces with gradual refractive transitions, reducing the overall reflected light ratio from 10.1% to below 1% across both front and rear surfaces.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies the moth-eye structure treatment specifically to the outer surfaces of the transparent film where light reflection occurs, while maintaining the bulk material properties for protection. This localized modification reduces reflected light without compromising the film's overall protective function or transparency.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If conventional transparent films are used in high-intensity surgical lighting environments, then face protection is achieved, but fogging occurs reducing visibility

Engineering Contradiction:
ImprovefoggingVSAvoidvisibility
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent extracts the anti-fogging function from the base transparent film material and implements it as a separate hydrophilic coating layer on the film surface. This coating layer actively manages moisture condensation, preventing fogging that would otherwise occur in high-intensity surgical lighting environments, thereby maintaining visibility.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a composite structure combining a transparent plastic film base material with a hydrophilic coating layer. This composite material integrates both protective transparency and anti-fogging properties, solving the visibility reduction problem caused by fogging while maintaining face protection capabilities.

Inventive Principle:
Principle #40Composite materials

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 effectively reduces light reflection and prevents fogging, providing a clear field of view even under high-intensity surgical lighting conditions, ensuring improved visibility and comfort during surgical operations.

Implementation Method 1

multiple structures comprising recesses and protrusions, said structures being disposed on the surface of the substrate at a fine pitch shorter than the wavelength of visible light

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

The modulus of elasticity of a material forming the structures is 1 MPa to 1200 MPa, and the surface on which the structures are form is hydrophilic

Methodology Applied
Scientific EffectOptical interference: Interference

Implementation Method 3

the surface on which the structures are form is hydrophilic

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 4

a contact angle of the main surface of the base, the main surface having the structures thereon, to pure water is 30° or less

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentEP2947483B1Optical element for facial protection
Publication Date: 2019.03.13 DEXERIALS CORP
  • EP2947483B1 patent drawingFigure 1~2B
  • EP2947483B1 patent drawingFigure 3
  • EP2947483B1 patent drawingFigure 4

AI summary

An optical element is provided which reflects a reduced amount of light even under a very high intensity lighting system used for a surgical operation, a dental treatment etc., has anti-fogging performance, and is transparent and useful for face protection. The optical element 1 has a flexible transparent substrate (a substrate 11) and a plurality of structures 12 disposed on opposite surfaces of the substrate at a pitch equal to or less than the wavelength of visible light. The structures 12 are formed from a cured product of a resin having a hydrophilic functional group.