Black Bank Resin Composition for OLED Light Reflection Control
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Solution Overview
Problem
Existing polyimide-based transparent banks in organic light emitting devices suffer from external light reflection issues, leading to image quality defects and reduced transmittance, which shortens the device's lifetime.
Innovation Solution
A negative type photosensitive resin composition is developed, comprising a specific compound, an alkali soluble resin binder, a polyfunctional monomer, a colorant, a photoinitiator, and a solvent, along with a fluorine-based or silicone-based surfactant, to form a black bank that effectively blocks external light reflection and maintains uniform optical density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a transparent bank is used, then the device structure is simple and manufacturing is easier, but external light reflection occurs causing image quality defects
Solution Approach 1:
The patent applies a black bank structure that changes the optical property from transparent to light-absorbing black color. The black bank material absorbs external light instead of reflecting it, eliminating image quality defects caused by light reflection while maintaining manufacturing simplicity through a single-layer structure.
Solution Approach 2:
The patent uses a composite material structure consisting of a black bank layer formed by a photosensitive resin composition containing black pigment mixed with binder resin. This composite approach combines the light-absorbing property of black pigment with the adhesion and structural properties of the binder, effectively blocking external light reflection.
2Object-affected harmful factors
If a polarizing plate is added to reduce external light reflection, then light reflection is improved, but transmittance is significantly reduced requiring higher voltage driving
Solution Approach 1:
The black bank structure changes the approach from using a polarizing plate to directly absorbing light through black pigment. This eliminates the need for polarizing plates and their associated transmittance losses, allowing normal voltage driving without energy consumption issues.
3Object-affected harmful factors
If the black bank thickness is increased to improve optical density, then light blocking is improved, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent uses a photosensitive resin composition that is applied as a coating and then patterned through photolithography. The preliminary coating step allows for uniform thickness deposition, and the subsequent photopatterning process precisely defines the final black bank thickness and shape, enabling good manufacturing precision.
Solution Approach 2:
The patent optimizes the resin composition parameters including the type and amount of black pigment, binder resin, and solvents to achieve the desired optical density. By adjusting these compositional parameters rather than simply increasing thickness, the patent achieves effective light blocking while maintaining manufacturability.
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 resin composition improves image quality by reducing external and metal reflections, allowing for the formation of a black bank with a predetermined thickness, thereby enhancing the optical density and extending the lifetime of the organic light emitting device.
Implementation Method 1
a photoinitiator
Implementation Method 2
a colorant
Data Source
AI summary
The present application relates to a negative type photosensitive resin composition including a compound of Chemical Formula 1, an alkali soluble resin binder, a polyfunctional monomer, a colorant, a photoinitiator, and a solvent, and a display apparatus including a black bank formed by using the same.