Pixel-Defining Layer Composition for Flexible Display Light Blocking
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Solution Overview
Problem
Existing organic light emitting display devices face challenges in reducing reflectivity around 550 nm, which affects visibility, and lack a suitable replacement for polarizing films that are not flexible.
Innovation Solution
A photosensitive resin composition is used to form a pixel defining layer with an optical density of 0.8/μm to 1.5/μm and reflectivity of 0.01% to 6.5%, incorporating inorganic and organic pigments, with a post-baking process at 250° C to 270° C for 60 to 120 minutes, to create a flexible light blocking layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a polarizing film is used to block reflected light, then the antireflection effect is improved, but the device loses flexibility and cannot be applied to flexible displays
Solution Approach 1:
The patent replaces the mechanical/polarizing film-based light blocking system with a photosensitive resin composition system that uses photochemical reactions and pigment absorption to achieve the same light blocking function while enabling flexibility. The photosensitive resin with pigments provides the antireflection effect through optical absorption rather than polarization, allowing the display to be flexible.
Solution Approach 2:
The patent changes the material parameters by using a photosensitive resin composition with specific pigment concentrations and optical properties instead of traditional polarizing films. By controlling the optical density (0.8/μm to 1.5/μm) and reflectivity (0.01% to 6.5%), the system achieves both light blocking and flexibility.
2Illumination intensity
If the optical density is increased to block more light, then the visibility and color vividness are improved, but the reflectivity around 550 nm increases which reduces visibility
Solution Approach 1:
The patent optimizes the optical parameters by controlling the optical density within a specific range (0.8/μm to 1.5/μm) and adjusting pigment concentrations (17 wt % to 35 wt %) to achieve the desired balance between light blocking and reflectivity control around 550 nm.
Solution Approach 2:
The patent uses composite materials combining photosensitive resin with various pigments (organic and inorganic) to achieve both high optical density for color vividness and controlled reflectivity. The composite structure allows simultaneous optimization of multiple optical properties that would be difficult to achieve with single materials.
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 solution enhances visibility by reducing reflectivity, enabling flexible displays with improved image quality and vivid colors while maintaining reliability and extending the display's lifetime.
Implementation Method 1
exposure to light of the photosensitive composition
Implementation Method 2
the optical density (OD) becomes higher in order to block light being transmitted from the outside or light being reflected from the bottom
Implementation Method 3
post-baking of the photosensitive composition
Data Source
AI summary
An object of the present disclosure is to implement a coloring pattern with a high optical density on an electrode substrate to improve display reliability and lifetime of a display as well as vivid colors. That is, the present disclosure relates to a composition and a method that can form the pattern of a pixel defining layer that can improve visibility and contrast by satisfying the optical density of 0.80/μm to 1.5/μm in the panel after post-baking treatment.