Hologram Recording Medium Composition for Heat-Moisture Stability

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Solution Overview

Problem

Hologram recording media used in high temperature/high humidity environments, such as mobile devices and vehicle parts, suffer from deformation of diffraction gratings, leading to distorted images and impaired functionality.

Innovation Solution

A hologram recording medium comprising a photopolymer layer with a specific element ratio of carbon, nitrogen, oxygen, fluorine, and silicon, formed by crosslinking a siloxane-based polymer and a (meth)acrylic-based polyol, and including a photoreactive monomer and photoinitiator system, which enhances durability and adhesion while maintaining optical recording characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a photopolymer layer is used for hologram recording, then diffraction efficiency and refractive index modulation are improved, but deformation occurs in high temperature/high humidity environments

Engineering Contradiction:

Improvestability of hologramVSAvoiddeformation of diffraction grating

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent modifies the chemical composition parameters of the photopolymer layer by incorporating specific ratios of fluorinated compound (3-12 atomic%), silicon (3-15 atomic%), and oxygen (15-30 atomic%). These parameter changes enhance the thermal and moisture resistance of the photopolymer, preventing deformation of the diffraction grating in high temperature/high humidity environments while maintaining hologram stability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite photopolymer material combining siloxane-based polymer, (meth)acrylic-based polyol, fluorinated compound, and photoreactive monomer. This composite structure leverages the heat resistance of siloxane bonds and the optical properties of the photoreactive components to achieve both structural stability and functional performance in harsh environments.

Inventive Principle:

Principle #40Composite materials

2Productivity

If photopolymerization is induced by laser interference light, then hologram recording is achieved, but heat generation may cause deformation

Engineering Contradiction:

Improvehologram recording efficiencyVSAvoidheat generation during exposure

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent converts the harmful heat generated during laser exposure into a beneficial effect by incorporating fluorinated compounds and siloxane-based polymers that utilize thermal energy to enhance crosslinking density and structural stability. The heat that would normally cause deformation instead strengthens the photopolymer network, improving resistance to subsequent thermal deformation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If thin photopolymer layer is used, then angular selectivity increases, but mechanical strength and environmental resistance decrease

Engineering Contradiction:

Improveangular selectivityVSAvoidmechanical strength of photopolymer layer

Core Design Contradiction:

Measurement precisionVSStrength

Solution Approach 1:

The patent changes the chemical composition parameters to include high ratios of fluorine (3-12 atomic%) and silicon (3-15 atomic%), which enable the thin photopolymer layer to achieve enhanced mechanical strength and environmental resistance. The fluorinated compound and siloxane-based polymer create a densely crosslinked network that provides structural integrity even in thin layers, maintaining angular selectivity while improving strength.

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

The solution provides a hologram recording medium with improved durability against heat and moisture, maintaining optical recording characteristics and transparency, and preventing deformation of diffraction gratings.

Implementation Method 1

a photopolymer layer which includes a polymer matrix formed by crosslinking a siloxane-based polymer containing a silane functional group and a (meth)acrylic-based polyol, or a precursor thereof; a photoreactive monomer and a photoinitiator system

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

a polymer matrix formed by crosslinking a siloxane-based polymer containing a silane functional group and a (meth)acrylic-based polyol

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Data Source

PatentUS20250362644A1Hologram recording medium, preparation method thereof and optical element comprising the same

Publication Date: 2025.11.27 LG CHEM LTD

AI summary

The present invention relates to a hologram recording medium, a preparation method thereof, and an optical element including the same. As the hologram recording medium satisfies a specific element ratio, it not only is excellent in optical recording characteristics, but also exhibits excellent durability against heat and moisture, and can exhibit appropriate adhesive force to transparent adhesives and high transparency.