Caved Surface Cap for Organic EL Devices
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Solution Overview
Problem
Organic electroluminescent (EL) devices deteriorate due to moisture and oxygen, leading to reduced lifespan and contrast ratio issues caused by Newton's rings and light scattering, which affect luminescent efficiency and power consumption.
Innovation Solution
A cap with a caved surface is designed, featuring a minimum depth of 10 μm and a maximum depth of 10% of the total thickness, a refractive index of 1.6 to 2, and an angle of 60° or less between the bottom surface and the inclined surface, made from transparent materials like TiO2, BaO, and B2O3, to prevent Newton's rings and enhance stiffness and light inhibition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a flat cap is used to seal the organic EL device, then the sealing function is achieved, but Newton's rings and light scattering occur causing reduced contrast ratio and luminescent efficiency
Solution Approach 1:
The patent applies curvature by forming a caved surface (concave structure) in the center of the cap's lower surface. This curved geometry eliminates the parallel flat surfaces that cause Newton's rings and light scattering, thereby improving contrast ratio and luminescent efficiency without compromising the sealing function.
2Loss of energy
If the cap thickness is reduced to minimize light loss, then light inhibition is improved, but the cap becomes less stiff and more susceptible to external physical impacts
Solution Approach 1:
The caved surface design creates a curved structure that inherently increases structural stiffness and impact resistance even when the cap thickness is minimized. The concave geometry distributes mechanical stress more effectively, allowing the cap to remain protective while minimizing light loss through reduced material thickness.
Solution Approach 2:
The invention introduces a vertical dimension to the cap surface by creating a caved structure with specific depth (10-100 μm). This three-dimensional modification allows the cap to achieve both optical optimization (minimized light loss) and mechanical optimization (enhanced stiffness) simultaneously, rather than being constrained to a flat two-dimensional surface.
3Illumination intensity
If a cap with deep cave structure is used to prevent Newton's rings, then contrast ratio is improved, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent defines specific parameter ranges for the caved surface (depth: 10-100 μm, which is 10% or less of cap thickness; angle: 60° or less) to balance optical performance with manufacturing feasibility. These controlled parameters ensure sufficient contrast ratio improvement while maintaining reasonable manufacturing precision requirements.
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 prevents Newton's rings, improves contrast ratio, reduces external physical impacts, and decreases power consumption by minimizing light loss and increasing luminescent efficiency through the optimized cap design.
Implementation Method 1
contrast ratio issues caused by Newton's rings and light scattering
Implementation Method 2
contrast ratio issues caused by Newton's rings and light scattering
Implementation Method 3
a refractive index of 1.6 to 2
Data Source
AI summary
An organic electroluminescent (EL) device is provided that may include a first electrode, an organic layer and a second electrode arranged in a light-emitting region of a substrate. The device may also include a cap for sealing the light-emitting region of the substrate. The cap may have a caved surface with a minimum depth of 10 μm and a maximum depth of 10% of a total thickness of the cap.