Photosensitive Polyimide Composition for OLED Insulating Layers
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Solution Overview
Problem
Current positive photosensitive polyimide compositions for organic light-emitting devices face challenges with controlling taper angle, outgassing, adhesion, water repellency, and storage stability, limiting their commercialization and performance.
Innovation Solution
A positive photosensitive polyimide composition comprising polyimide, polyamic acid, and a photoactive compound, specifically designed to include a phenolic hydroxy group and silicon-based substituents for improved solubility and adhesion, along with a diazonaphthoquinone-based photoactive material for enhanced resolution and water repellency, using an alkali aqueous developing solution for environmental friendliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If positive photosensitive polyimide composition is used for organic light-emitting devices, then heat resistance and mechanical strength are improved, but control of taper angle and outgassing is difficult
Solution Approach 1:
The patent modifies the chemical composition parameters of the polyimide precursor by incorporating specific functional groups (carboxyl groups with controlled content of 1-50 mmol/g, hydroxyl groups, and silicon-based substituents) to alter the material's physical and chemical properties, thereby achieving better control over taper angle and outgassing while maintaining mechanical strength
Solution Approach 2:
The patent creates a composite polyimide system by combining polyimide precursor with specific additives including carboxyl-containing compounds, silicon-based compounds, and photoactive compounds, where each component contributes specific properties that collectively resolve the contradiction between mechanical strength and manufacturing precision
2Strength
If positive photosensitive polyimide composition is used, then adhesion and water repellency are improved, but storage stability deteriorates
Solution Approach 1:
The patent optimizes the functional group content parameters within specific ranges (carboxyl groups: 1-50 mmol/g, hydroxyl groups: controlled content) to achieve the right balance between adhesion performance and storage stability, preventing excessive reactivity that would compromise stability while maintaining sufficient adhesion
Solution Approach 2:
The patent introduces silicon-based substituents and specific functional groups at controlled concentrations to create localized regions with enhanced adhesion and water repellency properties without compromising the overall storage stability of the bulk material
3Manufacturing precision
If resolution is improved by using positive photosensitive polyimide, then fine shapes are easily obtained, but the difference in solubility between exposed and non-exposed portions is insufficient
Solution Approach 1:
The patent enhances the solubility difference by incorporating photoactive compounds that undergo significant chemical transformation upon exposure, creating a larger solubility contrast between exposed and non-exposed regions, which directly improves pattern resolution and formation reliability
Solution Approach 2:
The patent uses photoactive compounds as intermediaries that mediate the transformation of the polyimide precursor upon light exposure, facilitating a more pronounced solubility difference between exposed and non-exposed portions through chemical modification
4Ease of manufacture
If alkali aqueous solution is used as developing solution, then cost is reduced and environmental friendliness is improved, but the composition requires improved storage stability
Solution Approach 1:
The patent adjusts the chemical composition parameters of the polyimide precursor to enhance storage stability, allowing the use of cost-effective and environmentally friendly alkali aqueous developing solutions without compromising material stability during storage and processing
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 low taper angle, excellent adhesion, and water repellency, with improved storage stability and high resolution in organic insulating layers for OLEDs, reducing outgassing and enabling efficient manufacturing processes.
Implementation Method 1
a photoactive compound which has a structure represented by the following formula 3; wherein R1 to R6 independently represent a hydrogen atom, a hydroxyl group, a carboxyl group, an alkyl group, an alkoxy group, an aryl group or a substituted or unsubstituted heteroaryl group, and at least one of R1 to R6 is a carboxyl group
Implementation Method 2
a chemical amplification composition that is manufactured by mixing a resin that is obtained by substituting a carboxy group of a polyamic acid with an acetal group that is dissociated by an acid with a photoacid generating agent
Implementation Method 3
Photosensitive polyimide that has heat resistance is actively used
Data Source
AI summary
The present invention relates to a positive photosensitive polyimide composition that includes polyimide, a polyamic acid, and a photoactive compound. An organic insulating layer for organic light-emitting devices (OLED), which includes the positive photosensitive polyimide composition, may control a taper angle and outgassing, and has excellent adhesion in respects to a substrate, water repellent control ability, and storage stability and the like.