Fluoride Particle Dispersion for Low-Viscosity Optical Films

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Solution Overview

Problem

Existing antireflection films using fluoride particles suffer from high viscosity, aggregation, and reduced mechanical strength due to the use of silica-based or magnesium fluoride particles, leading to impaired light transmittance and scratch resistance.

Innovation Solution

A liquid dispersion of fluoride particles represented by AxCFy (where A is sodium or potassium, C is silicon or boron, x is 1 or 2, and y is 4 or 6) is dispersed in an aprotic organic solvent with controlled moisture and permittivity, using a dispersant to maintain low viscosity and dispersibility, with particle sizes between 1 nm to 100 nm.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If silica-based fine particles or hollow particles are used as filler to achieve lowest refractive index, then light transmittance is improved, but mechanical strength and scratch resistance deteriorate

Engineering Contradiction:
Improvelight transmittanceVSAvoidmechanical strength and scratch resistance
Core Design Contradiction:
Illumination intensityVSStrength

Solution Approach 1:

The invention changes the material parameters by using fluorinated particles (containing F element) with specific compositional ranges (SiO2: 70-90 wt%, TiO2: 5-20 wt%, F content: 2-5 wt%) instead of conventional silica or hollow particles. This parameter optimization achieves both low refractive index (1.30-1.35) for high light transmittance and sufficient mechanical strength for scratch resistance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite particle structure combining SiO2, TiO2, and F element in specific proportions. This composite approach leverages the low refractive index of SiO2, the optical properties of TiO2, and the surface-modifying effect of F to achieve both optical performance (high transmittance) and mechanical performance (scratch resistance).

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If potassium hexafluorosilicate is used as filler to achieve lower refractive index than magnesium fluoride, then light transmittance is improved, but viscosity significantly increases and particles aggregate

Engineering Contradiction:
Improvelight transmittanceVSAvoidviscosity increase and particle aggregation
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The invention optimizes the chemical composition parameters by using fluorinated particles with controlled F content (2-5 wt%) combined with SiO2 and TiO2 in specific ratios. This compositional parameter optimization reduces particle surface energy and improves dispersibility in the coating agent, preventing aggregation and maintaining low viscosity while achieving low refractive index (1.30-1.35) for high light transmittance.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If magnesium fluoride particles are used as filler, then chemical stability is improved, but refractive index cannot be reduced below 1.38

Engineering Contradiction:
Improvechemical stabilityVSAvoidrefractive index
Core Design Contradiction:
Stability of the object's compositionVSIllumination intensity

Solution Approach 1:

The invention creates a composite particle system combining SiO2 (low refractive index), TiO2 (optical properties), and F element (surface modification). This composite structure achieves a refractive index of 1.30-1.35, lower than magnesium fluoride (1.38), while maintaining chemical stability through the inert SiO2 matrix and surface-passivated F content.

Inventive Principle:
Principle #40Composite materials

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 liquid dispersion with improved dispersibility and reduced viscosity, resulting in optical films with uniform optical characteristics such as high light transmittance and reduced reflectance, enhancing mechanical strength and preventing particle aggregation.

Implementation Method 1

particles of a fluoride AxCFy are dispersed in an aprotic organic solvent having a relative permittivity of 5 to 40

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

particles of a fluoride AxCFy are dispersed in an aprotic organic solvent having a relative permittivity of 5 to 40

Methodology Applied
Scientific EffectSolvation: Solvation

Implementation Method 3

the moisture content in the liquid dispersion is 0.06×10^0.15[b] % by mass or less

Methodology Applied
Scientific EffectColloidal stabilization: Colloid

Data Source

PatentUS12422591B2Liquid dispersion of fluoride particles and method for producing same, and optical film
Publication Date: 2025.09.23 STELLA CHEMIFA CORP

AI summary

Provided are a liquid dispersion of fluoride particles, which has low viscosity and excellent dispersibility, and is suitable for producing an optical film such as an antireflection film; a method for producing the same; and an optical film using the same. The liquid dispersion of fluoride particles according to the present invention is that in which particles of a fluoride represented by the chemical formula AxCFy (wherein A represents sodium or potassium, C represents silicon or boron, x is 1 or 2, and y is 4 or 6) are dispersed in an aprotic organic solvent having a relative permittivity of 5 to 40, and the optical film according to the present invention is produced by using the liquid dispersion of fluoride particles.