Transparent Resin Layer for Organic EL Panels
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Solution Overview
Problem
Organic EL panels face low light extraction efficiency due to wavelength dependency of refractive index, leading to color unevenness and reduced light emission efficiency, particularly with blue light being confined within the panel.
Innovation Solution
A transparent resin layer with dispersed light-scattering particles or an uneven structure is applied to the organic EL panel, featuring a combination of fine particles with diameters ranging from 300 nm to 50,000 nm and projections with varying sizes and shapes to scatter light effectively across different wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a layer containing fine particles is provided on the light-transmitting substrate to scatter and diffuse light, then light extraction efficiency is improved, but wavelength dependency causes color unevenness and reduced efficiency for blue light
Solution Approach 1:
The patent changes the particle size parameter to resolve the wavelength dependency issue. By using particles with diameter of 1 μm or less (significantly smaller than conventional particles), the scattering mechanism changes to be more effective for short wavelengths (blue light) while maintaining effectiveness for longer wavelengths, thereby improving color uniformity while maintaining high light extraction efficiency
Solution Approach 2:
The patent uses composite materials by combining transparent resin with specific fine particles (inorganic particles such as SiO2, TiO2, ZnO, or organic particles) to create a light scattering layer that achieves both high light extraction efficiency and color uniformity. The composite structure allows optimization of scattering properties across different wavelengths
2Productivity
If scattering particles are added to improve light extraction, then light emission efficiency increases, but device complexity increases
Solution Approach 1:
The patent merges the light scattering function directly into the transparent substrate by forming a light scattering layer on the substrate surface. This integration eliminates the need for separate scattering layers or complex multi-layer structures, achieving high light emission efficiency while maintaining simple device structure and manufacturing process
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 light extraction efficiency, particularly for blue light, reducing color unevenness and increasing overall light emission, thereby improving the panel's performance and reducing power consumption.
Implementation Method 1
scattering and diffusion of light emitted from the organic EL layer is controlled by providing a layer containing fine particles
Implementation Method 2
a critical angle due to the differences in refractive index between the layers is generated
Implementation Method 3
the emitted light is totally reflected at the interfaces between the layers in the organic EL panel
Data Source
AI summary
To provide a transparent resin layer for use in an organic EL panel, capable of solving a problem with light extraction efficiency caused by the wavelength dependency (wavelength dispersion) of the refractive index of light. A transparent resin layer 12 for use in an organic EL panel includes: a transparent resin 121; and first fine particles 122 having an average particle diameter from 300 to 50000 nm and second fine particles 123 having an average particle diameter from 1 to 300 nm dispersed in the transparent resin 121, and the fine particles have a function as at least either a light scattering material or a light-dispersing material. Alternatively, a transparent resin layer 42 for use in an organic EL panel includes a transparent resin 421 having an uneven structure, the uneven structure includes first projections 422 in which at least either the widths or the heights are from 300 to 1000 nm and second projections 423 in which at least either the widths or the heights are from 10 to 300 nm, and at least either the shapes or the sizes of the projections in the uneven structure have no periodicity.