Silicone Antireflection Coating Thermal Stability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Silicones pose challenges for antireflection coatings due to their elastic behavior, high thermal expansion, and nonpolar surfaces, making it difficult to achieve durable bonding with conventional interference layers, and existing plasma etching processes are not suitable for silicone surfaces.

Innovation Solution

A method involving the application of a thermally stable organic layer with a reflection-reducing nanostructure produced by plasma etching, followed by a thin cover layer, which improves adhesion and maintains antireflection effectiveness over a wide range of wavelengths and temperatures, using materials like melamine and silicon oxide.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional interference layers made of oxides are applied on silicone surfaces, then antireflection is achieved, but the layers fracture and form cracks due to silicone's elastic behavior and thermal expansion

Engineering Contradiction:

Improvelight reflection lossVSAvoidcoating durability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The invention changes the material parameter from rigid brittle oxide layers to flexible polymer layers that can accommodate silicone's elastic behavior and thermal expansion, preventing fracture while maintaining antireflection properties

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses composite material structures including adhesion promoters and flexible polymer layers combined with silicone substrates, creating a multi-layer system that addresses both adhesion and flexibility requirements

Inventive Principle:

Principle #40Composite materials

2Illumination intensity

If rigid brittle oxide layers are used for antireflection, then optical performance is improved, but bonding fails due to silicone's elastic behavior and thermal expansion

Engineering Contradiction:

Improveoptical transmissionVSAvoidbonding strength

Core Design Contradiction:

Illumination intensityVSStrength

Solution Approach 1:

The invention changes the mechanical parameter of the coating from rigid to flexible by using polymer materials, enabling the coating to maintain bonding strength while accommodating substrate deformation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention introduces adhesion promoter layers as intermediary layers between the silicone substrate and the antireflection coating, improving chemical bonding while the flexible polymer layers provide mechanical compliance

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If plasma etching is used to create nanostructures, then antireflection is improved, but the process is not suitable for silicone surfaces

Engineering Contradiction:

Improvelight reflection lossVSAvoidprocess compatibility

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The invention replaces the plasma etching process with a spray coating process that uses chemical reactions to form nanostructured oxide layers on silicone surfaces, achieving antireflection without requiring plasma processing

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Ease of manufacture

If silicone surfaces are coated without activation, then coating process is simple, but the nonpolar surfaces cannot be wetted and coated

Engineering Contradiction:

Improvecoating process simplicityVSAvoidsurface wettability

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The invention performs preliminary surface activation using corona discharge or plasma treatment to create polar groups on the silicone surface, improving wettability and adhesion before applying the antireflection coating

Inventive Principle:

Principle #10Preliminary action

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 method achieves a robust antireflection effect with low residual reflection across various angles and wavelengths, ensuring the silicone surface remains effective at high temperatures, and the antireflection layer is thermally stable, suitable for continuous use above 100°C.

Implementation Method 1

the production of a reflection-reducing nanostructure in the organic layer by a plasma etching process

Methodology Applied

Scientific EffectPlasma etching: Plasma

Implementation Method 2

The organic layer is preferably applied by a vacuum process, for example, by thermal evaporation

Methodology Applied

Scientific EffectThermal evaporation: Evaporation

Data Source

PatentUS10656307B2Optical element

Publication Date: 2020.05.19 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

AI summary

An optical element is disclosed. In an embodiment an optical element includes a substrate having a silicone surface, an antireflection layer overlying the silicone surface, wherein the antireflection layer comprises a first organic layer having a reflection-reducing nanostructure, the nanostructure having a depth of at least 30 nm, and a cover layer overlying the first organic layer, the cover layer having a thickness of no more than 40 nm.