Hologram Recording Composition for Low-Fluorescence Index Modulation
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Solution Overview
Problem
Existing hologram recording materials face challenges with low recording density, optical noise, and instability of refractive index modulation structures, which affect archivability and compatibility with AR glasses for high-color reproducibility with low power consumption.
Innovation Solution
A photosensitive composition combining monofunctional and polyfunctional photopolymerizable monomers, represented by specific molecular structures, enhances transparency, polymerizability, and chemical stability while suppressing fluorescence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photopolymerizable monomers are used for hologram recording, then polymerization can proceed to form refractive index modulation structure, but phosphors are produced as by-products causing optical noise that reduces recording density
Solution Approach 1:
The invention extracts and eliminates the harmful phosphor by-product formation by selecting specific photopolymerizable monomers (compounds of formulas (1) and (2)) that do not generate phosphors during polymerization. This resolves the contradiction by removing the source of optical noise while maintaining the ability to form refractive index modulation structures for high-density hologram recording.
Solution Approach 2:
The invention changes the chemical parameters of the photopolymerizable monomers by specifying particular molecular structures (formulas (1) and (2)) with specific functional groups and structural characteristics that prevent phosphor formation. This parameter change eliminates optical noise while preserving polymerization functionality.
2Reliability
If styrene-type vinyl monomers are used to achieve high sensitivity and archivability, then polymerization efficiency improves, but the benzyl position becomes easily oxidized causing yellowing and poor weather resistance
Solution Approach 1:
The invention changes the chemical structure parameters by replacing styrene-type vinyl monomers with compounds of formulas (1) and (2) that have different molecular structures lacking the vulnerable benzyl position. This structural parameter change maintains archivability while eliminating the oxidation susceptibility that causes yellowing and coloration.
Solution Approach 2:
The invention uses a composite approach by combining specific monofunctional monomer (formula (1)) and polyfunctional monomer (formula (2)) with defined structural characteristics to create a polymer system that achieves both high archivability and resistance to yellowing, avoiding the drawbacks of conventional styrene-type monomers.
3Manufacturing precision
If dinaphthothiophene structure monomers are used to achieve extremely high refractive index modulation amount, then diffraction characteristics improve, but the composition becomes inherently prone to yellowing limiting use in optical materials
Solution Approach 1:
The invention changes the structural parameters by selecting monomers with formulas (1) and (2) that have different molecular structures from dinaphthothiophene compounds. These selected monomers achieve high refractive index modulation amounts while lacking the inherent yellowing tendency of dinaphthothiophene structures, enabling use in visible light optical materials.
4Manufacturing precision
If high refractive index modulation amount is achieved for better diffraction characteristics, then hologram performance improves, but optical noise such as fluorescence increases
Solution Approach 1:
The invention extracts and eliminates the source of fluorescence noise by selecting photopolymerizable monomers (formulas (1) and (2)) that do not exhibit fluorescence. This resolves the contradiction by removing the harmful fluorescence while maintaining high refractive index modulation amounts for excellent diffraction characteristics.
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 composition achieves high transparency, low fluorescence, and stable refractive index modulation, enabling long-term use in hologram recording media and AR glasses with improved diffraction characteristics.
Implementation Method 1
Irradiating a hologram recording material with interference fringes formed by interference of light allows photopolymerization to proceed at different polymerization rates in a bright part with high light intensity and in a dark part with low light intensity
Implementation Method 2
thereby forming a refractive index modulation structure while accompanying diffusion and migration of substances with different refractive indices
Implementation Method 3
at least one of the photopolymerizable monomers is a compound selected from a compound represented by Formula (1-1) below and a compound represented by Formula (1-2) below... R1 represents a fused aromatic ring group... R2 represents a fused aromatic ring group
Implementation Method 4
The present inventor has found that introducing a specific molecular structure into at least two different photopolymerizable monomers that are a combination of a monofunctional photopolymerizable monomer and a polyfunctional photopolymerizable monomer enables improvement in the archivability and suppression of the fluorescence phenomenon
Data Source
AI summary
A photosensitive composition for hologram recording, the photosensitive composition containing a photopolymerization initiator and at least two different photopolymerizable monomers that are a combination of a monofunctional photopolymerizable monomer and a polyfunctional photopolymerizable monomer. At least one of the photopolymerizable monomers is a compound represented by Formula (1-1) or (1-2) below, where A1 and A2 each are a photopolymerizable group; L1 and L2 each are a single bond or a divalent linking group that may be branched; R1 and R2 each are a fused aromatic ring group that may have a substituent; m1 is an integer of 2 to 5; m2 is an integer of 2 to 4; n is an integer of 2 to 4; when n is 2, X is a dimethylmethylene group or the like; when n is 3, X is a trivalent organic group; and when n is 4, X is a carbon atom or a silicon atom.