Light Emitting Display Apparatus Protrusion Bank Layer
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Solution Overview
Problem
Light emitting display apparatuses face inefficiencies in light extraction due to total reflection loss and waveguide loss, leading to trapped light within the device, which reduces their overall performance and power consumption.
Innovation Solution
The implementation of a light emitting display apparatus with a side mirror type anode and a bank layer featuring a light extraction pattern, including a protrusion portion and an inclined surface, enhances light extraction efficiency by redirecting trapped light towards the front direction and improving the refractive index mismatch at interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional light emitting display apparatus structure is used, then the device structure is simple, but light extraction efficiency is poor due to total reflection loss and waveguide loss
Solution Approach 1:
The patent introduces a three-dimensional protrusion structure on the overcoating layer surface, transforming the conventional two-dimensional flat surface into a multi-dimensional structure with varying heights and angles. This dimensional change creates multiple light extraction paths and reduces total reflection loss by altering the interface geometry between different layers.
Solution Approach 2:
The protrusion portions are designed with curved surfaces and inclined angles rather than sharp edges, creating smooth transitions that reduce light trapping. The curved geometry helps scatter trapped light toward the front direction, improving extraction efficiency while maintaining manufacturing feasibility.
2Ease of manufacture
If the overcoating layer has a flat upper surface, then the manufacturing process is simple, but light is trapped due to refractive index mismatch at interfaces
Solution Approach 1:
The overcoating layer is segmented into multiple regions with different heights (protrusion portions and base portions), creating a stepped or textured surface profile. This segmentation disrupts the uniform refractive index interface, reducing waveguide loss by preventing coherent light trapping while maintaining a relatively simple single-layer fabrication process.
Solution Approach 2:
The overcoating layer exhibits local quality variations through protrusion portions with different heights and surface characteristics in different regions. These localized structural modifications target specific areas where light trapping occurs, improving extraction efficiency without requiring complete restructuring of the entire layer.
3Loss of energy
If light is redirected using reflective layers, then light extraction efficiency improves, but device complexity increases
Solution Approach 1:
The protrusion structure itself serves the dual function of both light scattering and structural support, eliminating the need for separate reflective layers in some configurations. The geometric features of the protrusions create self-shadowing effects and multiple internal reflections that redirect light without requiring additional metallic reflective materials.
Solution Approach 2:
The protrusion portions act as intermediary structures between the light emitting layer and the external environment, mediating light extraction by creating gradual transitions and multiple interfaces. These intermediate structures reduce the abrupt refractive index mismatch without requiring direct contact between extreme materials.
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 configuration significantly increases the light extraction efficiency and power consumption benefits by effectively redirecting light that would otherwise be lost, enhancing the display's performance and energy efficiency.
Implementation Method 1
the total reflection loss refers to degradation of the light extraction efficiency due to light trapped in the light emitting display apparatus due to the total reflection at an interface between a substrate and air
Implementation Method 2
the reflective layer of the anode formed at the side portion of the protrusion portion can serve as a side mirror and some of light trapped in the light emitting display apparatus due to the total reflection is extracted to the front direction
Implementation Method 3
Light emitted from a light emitting layer of a general light emitting display apparatus
Data Source
AI summary
A light emitting display apparatus includes an overcoating layer on a substrate and including a base portion and a protrusion portion. The light emitting display apparatus further includes a first electrode disposed to cover the base portion and a side portion of the protrusion portion. The light emitting display apparatus further includes a bank layer on a part of the first electrode. The light emitting display apparatus further includes a light emitting layer on the first electrode and the bank layer. The light emitting display apparatus further includes a second electrode on the light emitting layer. The bank layer includes a first part on the protrusion portion, a second part surrounding the first part and including an inclined upper surface, and a light extraction pattern on the first part adjacent to the second part.