Zeolite Getter Particles in OLED Resin Layers
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Solution Overview
Problem
Organic light-emitting devices face issues with light transmission efficiency and display quality due to the presence of getter particles in the resin layer, which scatter light and allow external substances to degrade the organic layers, leading to cloudy phenomena and reduced contrast.
Innovation Solution
Incorporating particles with specific sizes and materials, such as synthetic zeolite, aluminum oxide, and silica gel, in the coating layer to maximize Mie-scattering efficiency while minimizing light scattering, thereby maintaining high light-emission quality and preventing functional degradation from external substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If getter particles are dispersed in the resin layer to capture water and oxygen, then protection of organic layers is improved, but light transmission and display quality deteriorate due to scattering
Solution Approach 1:
The patent applies parameter changes by optimizing the particle size of getter particles to a specific range (0.1 μm to 10 μm, preferably 0.5 μm to 5 μm) and controlling their concentration (0.1 wt% to 10 wt%, preferably 0.5 wt% to 5 wt%). This parameter optimization ensures that particles are small enough to minimize light scattering while large enough to maintain effective water and oxygen absorption capacity, thereby resolving the contradiction between protection functionality and light transmission efficiency
Solution Approach 2:
The patent implements local quality by creating a multi-size particle distribution system where particles of different sizes serve different functions. Smaller particles (closer to 0.1 μm) primarily handle light transmission while larger particles (up to 10 μm) provide enhanced gettering capacity. This localized functional differentiation within the particle population allows simultaneous achievement of both light transmission and protection functions
2Reliability
If particles are added to the coating layer to improve protection, then reliability is improved, but a cloudy phenomenon occurs reducing contrast
Solution Approach 1:
The patent resolves the cloudy phenomenon issue by changing the particle size parameter to fall within the Mie scattering optimal range (0.1 μm to 10 μm). This specific size range minimizes unwanted light scattering that causes cloudiness while maintaining effective protection. The controlled particle concentration (0.1 wt% to 10 wt%) further prevents excessive scattering that would degrade display contrast
Solution Approach 2:
The patent employs composite materials by combining getter particles with specific resin matrices that have complementary optical properties. The resin material is selected to have refractive index matching characteristics that reduce light scattering at particle-resin interfaces, thereby minimizing cloudy appearance while maintaining the protective gettering function of the dispersed particles
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 achieves high light-emission quality and light-extraction efficiency by inhibiting cloudy phenomena and protecting the organic layers from water and oxygen, ensuring superior display performance.
Implementation Method 1
when a particle size parameter (size parameter; πD/(λ/n)) is plotted on a horizontal axis and scattering efficiency Qc (=scattering sectional area/geometrical sectional area) is plotted on a vertical axis, an average particle size D50 of the plurality of particles is set in a range equal to or greater than a value of the particle size parameter at which the scattering efficiency becomes maximum
Implementation Method 2
particles (getter particles) that have hygroscopicity, thereby capturing substances such as water and oxygen, and protecting the organic layers
Data Source
AI summary
A display panel includes a EL panel part, a CF panel part, and a resin layer. Light is extracted from a luminous part including an organic luminous layer in the EL panel part in a direction of an arrow. The resin layer is formed to cover an upper surface of the EL panel part. Transmittance of the light from the EL panel part is 80% or higher. The resin layer includes a resin part and a plurality of particles dispersed in the resin part. The particles are formed of synthetic zeolite having a refractive-index ratio to the resin part of 1.0 or more and a particle size of 2 μm or more.