Hologram Recording Medium Composition for Low Haze and Diffraction Efficiency
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Solution Overview
Problem
Existing hologram recording media face challenges in achieving high diffraction efficiency and visibility while maintaining physical properties, with issues arising from the compatibility and composition of photopolymer layers.
Innovation Solution
A hologram recording medium comprising a photopolymer layer with a specific elemental ratio of fluorine (0.05 to 3 atomic %) on its surface, formed by crosslinking a siloxane-based polymer with a silane functional group and an acrylic-based polyol, along with a photoreactive monomer and photoinitiator system, enhances compatibility and reduces haze, thereby improving visibility and optical recording characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the photopolymer layer thickness is decreased to increase angular selectivity, then angular selectivity is improved, but diffraction efficiency deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the photopolymer layer by incorporating specific compounds (compound A with refractive index 1.50-1.65 and compound B with refractive index 1.30-1.45) to optimize the refractive index modulation. This allows achieving high diffraction efficiency even in thin layers (5-30 μm) while maintaining angular selectivity, thus resolving the contradiction between layer thickness reduction and diffraction efficiency maintenance.
Solution Approach 2:
The patent uses a composite photopolymer system combining multiple components: polymer matrix, photoreactive monomer, compound A (high refractive index), and compound B (low refractive index). This composite structure enables simultaneous optimization of diffraction efficiency and angular selectivity by creating multiple refractive index gradients within the layer, allowing thin layers to achieve both high DE and AS.
2Reliability
If the refractive index modulation value is increased to improve diffraction efficiency, then diffraction efficiency is improved, but compatibility between layers deteriorates
Solution Approach 1:
The patent optimizes the refractive index parameters by selecting compound A with refractive index 1.50-1.65 and compound B with refractive index 1.30-1.45, creating a controlled refractive index difference (Δn = 0.15-0.30). This parameter optimization achieves sufficient diffraction efficiency while maintaining compatibility, as the refractive index difference is neither too large (which would cause phase separation) nor too small (which would reduce DE).
Solution Approach 2:
The patent introduces compound B as an intermediary substance with intermediate refractive index (1.30-1.45) between the high refractive index compound A (1.50-1.65) and the polymer matrix. This intermediary helps bridge the refractive index gap, reducing abrupt changes that would cause incompatibility while still providing sufficient modulation for high diffraction efficiency.
3Illumination intensity
If the photopolymer layer is made thinner to reduce haze and improve visibility, then visibility is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the optical parameters by incorporating compounds with specific refractive indices to enhance the refractive index modulation capability. This allows achieving high visibility and low haze in thin layers (5-30 μm) because the enhanced Δn provides stronger diffraction contrast, compensating for the reduced layer thickness and making manufacturing precision requirements more manageable.
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 proposed composition maintains excellent optical recording characteristics and visibility by optimizing the fluorine content, ensuring low haze and high diffraction efficiency, while providing improved heat and moisture resistance.
Implementation Method 1
a photopolymer layer which includes a polymer matrix formed by crosslinking a siloxane-based polymer containing a silane functional group and an acrylic-based polyol; a photoreactive monomer and a photoinitiator system
Implementation Method 2
based on the total amount of carbon, oxygen, fluorine and silicon atoms on the surface of the photopolymer layer confirmed by Electron Spectroscopy for Chemical Analysis (ESCA), an element ratio of fluorine is 0.05 to 3 atomic %
Implementation Method 3
a polymer matrix formed by crosslinking a siloxane-based polymer containing a silane functional group and an acrylic-based polyol
Data Source
AI summary
The present disclosure relates to a hologram recording medium, a preparation method thereof, and an optical element including the same. The hologram recording medium can have excellent optical recording characteristics and low haze by controlling an element ratio of fluorine on the surface of the photopolymer layer to a specific range, and can provide an optical element with excellent visibility.