Organic Light Emitting Display with Desiccant and Edge Seal
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Solution Overview
Problem
Organic light emitting displays face challenges with narrow viewing angles due to increased cell gaps from face seal schemes, water and oxygen penetration, and light distortion from refractive index differences, which hinder high resolution and visibility.
Innovation Solution
The use of a desiccant in an edge seal scheme to minimize cell gaps, combined with a medium layer for refractive index matching between substrates, enhances the viewing angle and reduces the bezel area, while the desiccant and encapsulation unit prevent water and oxygen ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a face seal scheme is used to bond upper and lower substrates, then sealing performance is improved, but cell gap increases due to face seal thickness, narrowing viewing angle
Solution Approach 1:
The sealing structure is divided into two parts: an edge seal that bonds the periphery of upper and lower substrates, and a desiccant filling the internal space. This segmentation allows the edge seal to provide sealing without increasing cell gap, while the desiccant protects internal elements from humidity penetration.
Solution Approach 2:
A desiccant is introduced as an intermediary substance filling the space between substrates. It serves dual functions: preventing humidity penetration to organic light emitting elements and maintaining a minimal cell gap for enhanced viewing angle, while the edge seal provides structural bonding.
2Reliability
If encapsulation layers are added to prevent water and oxygen penetration, then reliability is improved, but device complexity and bezel area increase
Solution Approach 1:
The desiccant acts as an intermediary protective medium filling the cavity between substrates, preventing water and oxygen from reaching organic light emitting elements. This eliminates the need for multiple alternating organic and inorganic encapsulation layers, reducing device complexity and bezel area while maintaining protection.
Solution Approach 2:
The desiccant creates a humidity-free inert environment within the display device, protecting sensitive organic components from degradation by water and oxygen without requiring complex multi-layer encapsulation structures.
3Ease of manufacture
If different refractive index materials are used in substrates and encapsulation, then manufacturing ease is improved, but light distortion occurs, reducing visibility
Solution Approach 1:
The desiccant is selected to have a refractive index matching that of the upper and lower substrates (approximately 1.5). This homogeneity in refractive index across different layers eliminates light distortion and visibility issues while maintaining manufacturing flexibility.
4Length of moving object
If edge seal scheme with desiccant is used, then cell gap is minimized for better viewing angle, but sealing performance must be maintained
Solution Approach 1:
The sealing function is segmented between the edge seal that provides mechanical bonding and sealing at the periphery, and the desiccant that fills the internal space to prevent humidity penetration. This allows minimal cell gap for viewing angle enhancement while maintaining comprehensive sealing performance.
Solution Approach 2:
The desiccant serves as an intermediary protective medium that fills the cavity space, providing humidity barrier protection without requiring thick sealing layers, thus enabling minimal cell gap while maintaining sealing integrity.
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
This approach improves the viewing angle, aperture ratio, and visibility by reducing cell gaps and minimizing water and oxygen penetration, thereby enabling a high resolution display with enhanced optical performance.
Implementation Method 1
a desiccant fills a space between the lower substrate and the upper substrate
Implementation Method 2
The medium layer has a refractive index substantially identical to a refractive index of the upper substrate
Data Source
Figure 1a
Figure 1b~1c
Figure 1d
AI summary
There are provided an organic light emitting display and a method of manufacturing the organic light emitting display. The organic light emitting display includes a lower substrate including a plurality of subpixel regions, a thin film transistor formed on the lower substrate, an organic light emitting element formed on the thin film transistor, an encapsulation unit for covering the organic light emitting element, a spacer formed on the encapsulation unit, an upper substrate disposed to face the lower substrate, and a desiccant between the lower substrate and the upper substrate. Various embodiments of the invention provide an organic light emitting display that enhances a viewing angle by minimizing a cell gap and minimizing a distortion of light, minimizes penetration of water or oxygen from the outside, and realizes a high resolution display by enhancing an aperture ratio, and a method of manufacturing the organic light emitting display.