Pixel Defining Layer Photosensitive Resin Composition
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Solution Overview
Problem
Existing methods for preparing pixel defining layers in organic light-emitting display devices face challenges in reducing reflectivity around 550 nm, which affects visibility, and in achieving a stable dielectric constant despite changes in pigment content, which can lead to touch defects.
Innovation Solution
A method involving a photosensitive resin composition is used to prepare a pixel defining layer through application, prebaking, exposure, development, and post-baking, resulting in a layer with an optical density of 0.80/μm to 1.5/μm, a permittivity of 5.0 or less, and a reflectivity of greater than 0.01% and less than 6.5%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If materials with high permittivity (metal film or carbon black) are used as pixel defining layers to achieve excellent light shielding, then visibility is satisfactory, but permittivity becomes 5.0 or higher causing current flow to panel touch parts and resulting in touch defects
Solution Approach 1:
The patent changes the permittivity parameter of the pixel defining layer material from high (≥5.0) to low (≤5.0) by using photosensitive resin composition instead of metal film or carbon black, thereby preventing current flow to touch parts while maintaining light shielding function through optimized optical density (0.80/μm to 1.5/μm)
Solution Approach 2:
The patent employs a composite photosensitive resin composition containing pigment, binder resin, and curing agent that combines the light shielding capability of pigments with the low permittivity characteristic of resin materials, achieving both visibility and touch reliability
2Object-affected harmful factors
If pigment content is increased to achieve higher optical density and better visibility, then light shielding improves, but permittivity becomes unstable and may exceed 5.0 causing touch defects
Solution Approach 1:
The patent optimizes the pigment content parameter within a specific range (5-50 wt%) and adjusts the binder resin content accordingly to maintain permittivity at 5.0 or less, achieving stable composition that prevents touch defects while ensuring adequate light shielding
Solution Approach 2:
The patent uses a composite photosensitive resin composition where the binder resin acts as a matrix to disperse pigment particles uniformly, stabilizing the permittivity of the composite material even when pigment content varies within the optimized range
3Ease of manufacture
If conventional methods are used to prepare pixel defining layers, then manufacturing process is simple, but reflectivity around 550 nm cannot be reduced below 6.5% affecting visibility
Solution Approach 1:
The patent optimizes multiple parameters including optical density (0.80/μm to 1.5/μm), pigment content (5-50 wt%), and binder resin content to achieve reflectivity below 6.5% while maintaining a straightforward photo-lithography manufacturing process
Solution Approach 2:
The patent replaces conventional material deposition methods with photo-lithography processing, using light-based chemical reactions to form the pixel defining layer pattern, thereby achieving precise control over reflectivity and optical density while maintaining ease of manufacture
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 method effectively reduces reflectivity around 550 nm, improves visibility, and maintains a stable dielectric constant, thereby enhancing the reliability and lifespan of the display while preventing touch defects.
Implementation Method 1
a photosensitive composition is used to prepare a pixel defining layer through application, prebaking, exposure, development, and post-baking
Implementation Method 2
the higher the optical density (OD) to block externally transmitted light or light reflected from below, the more excellent the visibility
Implementation Method 3
performing post-baking treatment, wherein after the post-baking treatment step, the pixel defining layer has an optical density of 0.80/μm to 1.5/μm, a permittivity of 5.0 or less
Data Source
AI summary
Provided is a method to prevent interference between electrodes that causes pixel defects in a pixel defining layer, thereby lowering the touch defect rate of the panel, and implementing a coloring pattern with high optical density on the electrode substrate to not only make the colors vivid but also increase the reliability and lifespan of the display, particularly a composition and a method for forming a pixel defining layer pattern, which comprises a colorant, and the coating film formed by treating at high temperature during post-baking treatment has a high optical density (OD) per thickness, has a low permittivity of 5.0 or less even with changes in measured Hz, and can improve visibility and contrast.