Display Device Sealing Layer Irregularities for Light Extraction
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Solution Overview
Problem
Existing display devices face challenges in achieving high luminance, high color purity, and wide viewing angle while maintaining light extraction efficiency due to the introduction of a multilayer sealing structure, which causes reflection at interfaces and reduces light extraction efficiency.
Innovation Solution
A display device with a sealing layer comprising multiple stacked layers, where at least one interface between adjacent layers has irregularities or an intermediate layer with fine particles to scatter light, enhancing light convergence or diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multilayer sealing structure is introduced to improve covering property and strength, then sealing performance is improved, but light extraction efficiency is reduced due to reflection at interfaces
Solution Approach 1:
An intermediate layer is introduced between the first and second inorganic layers to serve as a light scattering mediator. This intermediate layer contains fine particles that scatter light, preventing direct reflection at the inorganic layer interfaces while maintaining the sealing function of the multilayer structure.
Solution Approach 2:
The sealing layer is designed with spatially varying properties: the intermediate layer containing light-scattering fine particles is positioned specifically between the inorganic layers where light transmission occurs, while the inorganic layers maintain their barrier properties. This local differentiation allows simultaneous achievement of sealing performance and light extraction efficiency.
2Illumination intensity
If optical sheets or optical structures are added to achieve high luminance and wide viewing angle, then display performance is improved, but light extraction efficiency is reduced due to increased interfaces
Solution Approach 1:
The refractive index parameter is optimized by selecting specific materials for the intermediate layer and fine particles. The fine particles have refractive indices that create strong light scattering effects, enabling high luminance without requiring additional optical sheets that would increase interface losses.
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 effectively achieves high luminance, high color purity, or wide viewing angle by minimizing light extraction efficiency reduction, even with a multilayer sealing structure, through light convergence or scattering at the interfaces.
Implementation Method 1
light can be converged or diffused by the irregularities located at the interface between the two adjacent layers of the sealing layer
Implementation Method 2
light can be converged or diffused by the irregularities located at the interface between the two adjacent layers of the sealing layer
Implementation Method 3
light can be scattered by the fine particles contained in the intermediate layer of the sealing layer
Data Source
AI summary
A display device includes: a plurality of pixel electrodes respectively corresponding to a plurality of unit pixels that constitute an image; a light-emitting element layer stacked on the plurality of pixel electrodes so as to be in contact with each of the plurality of pixel electrodes and provided so as to emit light with a luminance controlled by an electric current; a common electrode provided so as to be stacked on and in contact with the light-emitting element layer above the plurality of pixel electrodes; and a sealing layer made of a light-transmissive material and stacked on the common electrode so as to seal the light-emitting element layer. The sealing layer is formed of a plurality of layers that are stacked on one another. The interface between two adjacent layers of the plurality of layers includes irregularities in regions located above the plurality of pixel electrodes.