Dispersion Composition for High Refractive Index Microlenses
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Solution Overview
Problem
Existing compositions for forming high refractive index materials used in microlenses and solid-state imaging devices suffer from deteriorated coated surface conditions due to phase separation between inorganic particles and dispersion resins, particularly when the acid value of the dispersion resin is high, leading to uneven film surfaces.
Innovation Solution
A dispersion composition comprising metal oxide particles with a primary particle diameter of 1 nm to 100 nm, a polymer compound with an acid value of less than 120 mgKOH/g, and a solvent, where the polymer compound is represented by specific formulas and has a weight average molecular weight of 5,000 to 8,000, ensuring excellent steric repulsion and interaction with metal oxide particles to prevent aggregation and phase separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a dispersion resin with high acid value (120 mgKOH/g or more) is used to form a high refractive index material, then the refractive index is improved, but the coated surface conditions deteriorate due to phase separation between inorganic particles and dispersion resin
Solution Approach 1:
The patent changes the acid value parameter of the dispersion resin from 120 mgKOH/g or more to less than 120 mgKOH/g. This parameter change prevents acid group aggregation and phase separation between inorganic particles and dispersion resin, thereby maintaining excellent coated surface conditions while achieving high refractive index (1.7 or more) in the cured film.
2Illumination intensity
If the acid value of dispersion resin is increased to enhance dispersibility, then the refractive index is improved, but acid groups aggregate and cause phase separation
Solution Approach 1:
The patent applies parameter change by controlling the acid value of the dispersion resin to be less than 120 mgKOH/g. This prevents aggregation of acid groups and maintains compositional stability by avoiding phase separation between inorganic particles and dispersion resin, while still achieving the desired high refractive index.
3Productivity
If wafer size is increased to manufacture more devices in one process, then productivity is improved, but coated surface conditions deteriorate
Solution Approach 1:
The patent changes the acid value parameter of the dispersion resin to less than 120 mgKOH/g, which prevents acid group aggregation and phase separation. This enables uniform coating even on large wafers, thereby maintaining excellent coated surface conditions while supporting increased productivity through larger wafer sizes.
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 dispersion composition achieves a high refractive index and excellent surface conditions of the film after coating, enabling the formation of transparent films, microlenses, and solid-state imaging devices with improved light focusing and efficiency.
Implementation Method 1
a polymer compound (B) having an acid value of less than 120 mgKOH/g, which is represented by the following Formula (1)... ensuring excellent steric repulsion and interaction with metal oxide particles to prevent aggregation and phase separation
Implementation Method 2
a composition for forming a microlens having a high refractive index or for forming a solid-state imaging device, using silica-coated titanium oxide particles... a microlens having a higher refractive index is required... achieving more effective light focusing
Data Source
AI summary
There is provided a dispersion composition capable of forming a film being excellent in surface conditions, the dispersion composition containing metal oxide particles (A) having a primary particle diameter of 1 nm to 100 nm, a polymer compound (B) having an acid value of less than 120 mgKOH/g, which is represented by the following Formula (1), and a solvent (C).