Negative-Type Photosensitive Resin for High-Resolution Pixel Separation
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Solution Overview
Problem
Existing negative-type photosensitive resin compositions for organic electroluminescence (EL) displays are inadequate in terms of pattern shape, resolution, heat resistance, and light blocking properties, making them unsuitable for forming high-quality pixel-separating layers.
Innovation Solution
A negative-type photosensitive resin composition comprising a combination of polyimide, polybenzo-oxazole, polysiloxane, or cardo-based resins, along with a photopolymerization initiator and coloring agent, which allows for high-resolution, low-taper pattern formation and enhanced heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a negative-type photosensitive resin composition is used to form a pixel-separating layer with light blocking property, then external light reflection is reduced, but the pattern shape becomes rectangular or reversely tapered instead of low-taper
Solution Approach 1:
The patent changes the chemical composition parameters of the photosensitive resin by incorporating specific polymers (polyimide, polybenzo-oxazole, polysiloxane, cardo-based resin) and controlling the ratio of polymer components. This compositional parameter change enables the resin to form low-taper patterns while maintaining light blocking properties, resolving the contradiction between pattern shape and light reflection reduction.
Solution Approach 2:
The patent uses a composite photosensitive resin composition containing multiple polymer types (polyimide, polybenzo-oxazole, polysiloxane, cardo-based resin) with specific content ratios. This composite material approach combines the advantages of different polymers to achieve both low-taper pattern formation and effective light blocking, overcoming the limitation of conventional single-component resins that produce rectangular or reversely tapered patterns.
2Manufacturing precision
If conventional photosensitive resin compositions are used for pixel-separating layers, then pattern formation is achieved, but heat resistance is insufficient leading to ion component outflow and reduced service life
Solution Approach 1:
The patent employs a composite resin system combining polyimide, polybenzo-oxazole, polysiloxane, and cardo-based resins in specific ratios. This composite structure provides both the pattern formation capability needed for pixel separation and the high heat resistance required to prevent ion component outflow, thereby improving reliability while maintaining manufacturing precision.
Solution Approach 2:
The patent modifies the thermal stability parameters of the photosensitive resin by selecting polymers with high glass transition temperatures and stable molecular structures. The specific composition ratios are optimized to ensure the cured film maintains dimensional stability and prevents ion migration at elevated temperatures, solving the heat resistance issue while preserving pattern formation quality.
3Object-affected harmful factors
If acrylic resin is used as photosensitive material for black matrix, then light blocking property is achieved, but heat resistance is poor
Solution Approach 1:
The patent replaces conventional acrylic resin with a composite system of high-temperature-resistant polymers including polyimide, polybenzo-oxazole, polysiloxane, and cardo-based resins. This composite material maintains the light blocking capability needed for black matrix function while providing superior heat resistance to prevent degradation at display operating temperatures.
Solution Approach 2:
The patent fundamentally changes the thermal parameters of the photosensitive material by using polymers with high glass transition temperatures and stable chemical structures. The composition is designed to maintain mechanical integrity and optical properties at elevated temperatures, overcoming the heat resistance limitation of acrylic-based materials while preserving light blocking performance.
4Temperature
If polyamic acid is used for pixel-separating layer, then heat resistance is improved, but additional photoresist processing steps are required increasing complexity
Solution Approach 1:
The patent extracts the photosensitive functionality from the polyamic acid system and integrates it directly into the pixel-separating layer resin composition. By incorporating photopolymerization initiators and photo-reactive groups into the high-heat-resistance polymer matrix, the layer can be directly patterned without requiring a separate photoresist coating and development process, thereby reducing complexity while maintaining heat resistance.
Solution Approach 2:
The patent merges the functions of the pixel-separating layer material and the photoresist into a single integrated composition. The resin contains both the high-heat-resistance polymer matrix (polyimide, polybenzo-oxazole, polysiloxane, or cardo-based resin) and photo-reactive components, allowing direct photopatterning. This consolidation eliminates the need for separate photoresist processing steps while preserving the heat resistance properties.
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-resolution, low-taper patterns with improved heat resistance and light blocking properties, suitable for organic EL displays, while also enabling alkaline development.
Implementation Method 1
a negative-type photosensitive resin composition containing an (A1) first resin, a (A2) second resin, a (C) photopolymerization initiator, and a (D) coloring agent
Implementation Method 2
when a photosensitive resin composition is given a light blocking property, ultraviolet ray or the like at the time of pattern exposure will be blocked
Data Source
AI summary
To provide an alkaline developable negative-type photosensitive resin composition from which a cured film that has a high-resolution and low-taper pattern shape and that are excellent in heat resistance and light blocking property can be obtained. A negative-type photosensitive resin composition is characterized by containing an (A1) first resin, a (A2) second resin, a (C) photopolymerization initiator, and a (D) coloring agent, wherein the (A1) first resin is an (A1-1) polyimide and/or an (A1-2) polybenzo-oxazole, and wherein the (A2) second resin is one or more species selected from a (A2-1) polyimide precursor, a (A2-2) polybenzo-oxazole precursor, a (A2-3) polysiloxane, a (A2-4) cardo based resin, and an (A2-5) acrylic resin, and wherein a content ratio of the (A1) first resin in a total of 100 mass % of the (A1) first resin and the (A2) second resin is within the range of 25 to 90 mass %.