Hologram Medium Silane Crosslinking Refractive Index Modulation
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Solution Overview
Problem
Existing hologram media face challenges in achieving high refractive index modulation and diffraction efficiency, especially in thin thickness ranges, leading to image distortion and reduced diffraction efficiency due to non-uniform curing shrinkage and low crosslinking density.
Innovation Solution
A hologram medium comprising a polymer substrate with a silane-based functional group in the main or branched chain, which forms a fine pattern through uniform curing shrinkage, optimizing crosslinking density and refractive index modulation, and incorporating a silane crosslinking agent to enhance durability and mobility of photoreactive monomers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the photopolymer layer thickness is reduced to achieve thin film holograms, then the angular selectivity increases, but the refractive index modulation value decreases leading to low diffraction efficiency
Solution Approach 1:
The patent uses a composite photopolymer system combining polymer binder, monomer, crosslinking agent, and photoinitiator. The crosslinking agent forms a three-dimensional network structure that enhances refractive index modulation while maintaining thin film thickness, resolving the contradiction between thinness and modulation depth
Solution Approach 2:
The patent optimizes the composition ratios of polymer binder, monomer, and crosslinking agent to achieve high refractive index modulation in thin films. By adjusting these parameters, the system maintains both thin thickness and high diffraction efficiency
2Device complexity
If conventional photopolymer materials are used without crosslinking agents, then the formulation is simpler, but the curing shrinkage is non-uniform causing image distortion
Solution Approach 1:
The crosslinking agent acts as an intermediary that mediates the polymerization process, forming a three-dimensional network structure that constrains and uniformizes the curing shrinkage, thereby preventing image distortion while maintaining formulation simplicity
Solution Approach 2:
The crosslinking agent provides beforehand cushioning by creating a stable three-dimensional network structure that compensates for and uniformizes the curing shrinkage during polymerization, preventing image distortion before it occurs
3Speed
If the photopolymer layer is made thin to improve angular selectivity, then the response speed increases, but the diffraction efficiency decreases due to insufficient refractive index modulation
Solution Approach 1:
The composite photopolymer system with crosslinking agent achieves high refractive index modulation in thin films, simultaneously improving both angular selectivity response and diffraction efficiency by optimizing the material composition rather than sacrificing one for the other
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 hologram medium achieves high refractive index modulation and diffraction efficiency, with improved resistance to temperature and humidity, and maintains image sharpness by ensuring uniform fine patterns and optimized crosslinking, thereby enhancing recording characteristics.
Implementation Method 1
a photopolymer composition for hologram production comprises a polymer binder, a monomer, and a photoinitiator, and the photosensitive film produced from such a composition is irradiated with laser interference light to induce photopolymerization of local monomers
Implementation Method 2
the photosensitive film produced from such a composition is irradiated with laser interference light to induce photopolymerization of local monomers. In a portion where a relatively large number of monomers are present in such photopolymerization process, the refractive index becomes high
Implementation Method 3
the refractive index modulation occurs, and a diffraction grating is generated by such refractive index modulation
Data Source
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AI summary
The present disclosure relates to a hologram medium comprising: a polymer substrate including a polymer resin in which a silane-based functional group is located in a main chain or a branched chain, wherein a fine pattern is formed on at least one surface of the polymer substrate, and an optical element.