Metal Complex Composition for Refractive Index Gradient

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Solution Overview

Problem

Current methods for producing optical elements with gradient structures, such as holographic applications, face limitations in achieving sharp refractive index modulation, sensitivity, and refractive index bandwidth, leading to restricted resolution and efficiency, particularly due to slow diffusion and material shrinkage in thick layers.

Innovation Solution

A composition comprising an organic polymer and a metal complex with photosensitive groups, which decomposes to create a potential difference for directed diffusion and form a refractive index gradient, allowing for the production of optical elements with improved refractive index modulation and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the Colburn-Haines effect is used to generate refractive index gradients through monomer diffusion and local polymerization, then refractive index modulation is achieved, but the system exhibits limited sensitivity requiring high light intensity and long exposure time

Engineering Contradiction:
Improverefractive index modulation sharpnessVSAvoidexposure time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent changes the fundamental parameter of the photosensitive component from organic monomers to inorganic metal complexes with photosensitive groups. This parameter change enables the system to achieve the same refractive index modulation with significantly reduced exposure time and lower light intensity requirements, directly resolving the contradiction between modulation sharpness and exposure time.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by combining inorganic metal complexes with organic polymer matrices. This composite approach allows the inorganic component to provide high sensitivity and fast response for gradient formation, while the organic polymer matrix maintains mechanical stability and flexibility, achieving both sharp modulation and reduced exposure time simultaneously.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If inorganic components are introduced to increase refractive index bandwidth, then the bandwidth is improved, but material shrinkage increases due to radical polymerization

Engineering Contradiction:
Improverefractive index bandwidthVSAvoidmaterial shrinkage
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent extracts the polymerization function from the inorganic metal complex system by using a separate organic polymer matrix that does not undergo radical polymerization. The inorganic metal complex serves solely as the photosensitive component for gradient formation, while the organic polymer provides structural stability without causing shrinkage, thus resolving the contradiction between bandwidth and compositional stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the chemical nature of the matrix from a polymerizable organic system to a non-polymerizing organic polymer matrix. This parameter change eliminates the source of shrinkage (radical polymerization) while maintaining the refractive index bandwidth enhancement provided by the inorganic metal complex, achieving both goals simultaneously.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If nanoparticle concentration gradients are generated in composite materials to achieve high refraction efficiency, then refraction efficiency is improved, but layer thickness is limited and diffusion is slow

Engineering Contradiction:
Improverefraction efficiencyVSAvoiddiffusion speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent changes the diffusing species from nanoparticles to molecular-sized metal complex units. This parameter change dramatically increases the diffusion speed while maintaining the ability to form high-concentration gradients for efficient refraction. The smaller molecular size of the metal complex compared to nanoparticles enables faster diffusion through the matrix, resolving the contradiction between refraction efficiency and diffusion speed.

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

This method enables the production of optical elements with enhanced refractive index gradients, improving resolution and efficiency while maintaining mechanical flexibility and stability, and allowing for cost-effective and versatile production of optical elements suitable for various applications.

Implementation Method 1

at least one metal complex which contains at least one photosensitive group, the at least one metal complex of the formula X(m-n)MR1... which decomposes to create a potential difference for directed diffusion and form a refractive index gradient

Methodology Applied
Scientific EffectPhoto decomposition: Photodissociation

Implementation Method 2

This creates a potential difference which favors the diffusion of further metal complexes to this point, which are also decomposed. This leads to a change in the local refractive index at the point of decomposition and to the build-up of a refractive index gradient.

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP2347302B1Composition for producing optical elements having gradient structure
Publication Date: 2017.08.09 LEIBNIZ INSTITUT FUR NEUE MATERIALIEN GMBH
  • EP2347302B1 patent drawingFigure 1
  • EP2347302B1 patent drawingFigure 2
  • EP2347302B1 patent drawingFigure 3

AI summary

The invention relates to a composition for producing optical elements having a gradient structure, particularly for holographic applications, wherein the gradient structure is formed by a refractivity gradient. To this end, a composition is produced from a polymer and a light- and/or temperature-sensitive metal complex and the light- and/or temperature-sensitive metal complex is decomposed upon changing the local refractivity. The result is the formation of a refractivity gradient.