Titanium Dioxide Dispersion for High-Resolution Microlenses
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Solution Overview
Problem
Existing photosensitive resin compositions struggle to achieve high resolution and refractive index for microlenses used in solid-state image pick-up elements, particularly in achieving a resolution of 0.5 microns to 2 microns.
Innovation Solution
A dispersion composition comprising titanium dioxide particles with an average primary particle diameter of 1 nm to 100 nm, a graft copolymer with a graft chain of 40 to 10,000 atoms, and a solvent, where the graft copolymer includes structural units that enhance dispersibility and interaction with titanium dioxide, forming a photosensitive resin composition with a polymerizable compound and polymerization initiator for microlens formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If negative-type photosensitive resin compositions are used for microlens formation, then pattern formation process is simplified, but resolution of 0.5 microns to 2 microns cannot be achieved
Solution Approach 1:
The patent changes the particle size parameter of titanium dioxide from conventional larger sizes to ultra-fine particles with average primary particle diameter of 1 nm to 100 nm. This parameter change enables both high resolution patterning and maintains the usability of negative-type photosensitive resin compositions, resolving the contradiction between ease of manufacture and manufacturing precision.
Solution Approach 2:
The patent creates a composite photosensitive resin composition containing ultra-fine titanium dioxide particles dispersed in a specific resin matrix with controlled particle distribution. This composite material achieves both the resolution required for 0.5-2 micron microlenses and maintains good pattern formation characteristics, allowing simplified negative-type processing while achieving high manufacturing precision.
2Illumination intensity
If titanium dioxide content is increased to achieve high refractive index, then light concentration efficiency improves, but dispersibility and sedimentation control become difficult
Solution Approach 1:
The patent changes the particle size parameter to ultra-fine range (1-100 nm) and controls the particle size distribution to narrow ranges. This parameter change increases the surface area to volume ratio, improving dispersibility and reducing sedimentation while maintaining high refractive index through increased titanium dioxide content.
Solution Approach 2:
The patent applies local quality by ensuring uniform distribution of ultra-fine titanium dioxide particles throughout the photosensitive resin composition. The controlled particle size distribution creates local homogeneity in particle spacing and concentration, preventing aggregation and sedimentation while maintaining high overall refractive index.
3Manufacturing precision
If ultra-fine titanium dioxide particles are used to improve dispersibility, then resolution improves, but particle aggregation and sedimentation during storage increase
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: particle size (1-100 nm), particle size distribution (narrow range), and resin matrix composition. These parameter changes work together to provide steric stabilization and electrostatic repulsion that prevent aggregation and sedimentation of ultra-fine particles during storage, while maintaining the resolution benefits.
Solution Approach 2:
The patent uses a specifically designed resin matrix as an intermediary between ultra-fine titanium dioxide particles. The resin provides steric hindrance and electrostatic stabilization that prevents particle aggregation and sedimentation, acting as a mediator that maintains both the dispersed state for high resolution and the stability for long-term storage.
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 refractive index and transmittance, improved dispersibility, reduced residue generation, and enhanced surface uniformity, enabling the formation of high-resolution microlenses with increased titanium dioxide content.
Implementation Method 1
it has been found that when a graft copolymer having a specific structure is used as a dispersant, titanium dioxide can be dispersed in a photoensitive resin composition in a uniform state without aggregation
Implementation Method 2
a photosensitive resin composition including (A) titanium dioxide particles, (B) a graft copolymer, (C) a solvent, (D) a polymerizable compound, and (E) a polymerization initiator
Data Source
AI summary
A photosensitive resin composition which can form a pattern attaining high resolution and having a high refractive index and a high transmittance is provided. The photosensitive resin composition includes a dispersion composition including (A) titanium dioxide particles having an average primary particle diameter of from 1 nm to 100 nm, (B) a graft copolymer that has a graft chain having a number of atoms other than hydrogen atoms in a range of from 40 to 10,000 and (C) a solvent, and (D) a polymerizable compound, and (E) a polymerization initiator.